Singletary considers Bly over Brown for cornerback spot

Coach Mike Singletary hinted at personnel changes on Monday. He revealed a little more on Wednesday, the first day the 49ers began on-field work to face the Jaguars.

The 49ers own the league’s No. 29th30th-ranked pass defense, and Singletary said there might be some adjustments made in the secondary. When I asked if that meant veteran Dre’ Bly would take over for Tarell Brown at left cornerback, Singletary answered, “Possibly.”

If history has taught us anything, it’s that when Singletary said he is considering making a change, it usually means the change is made.

Bly has been a starter throughout his career. He’s been the team’s third defensive back the entire season. Brown is coming off a shaky performance against the Packers and he’s nursing a knee contusion.

Bly said he’s ready to start, and Brown said he’ll do whatever’s best for the team.

If Bly starts, he’ll see a lot of his good friend, receiver Torry Holt. These guys have known each other for a long time. They were heated rivals in college. Bly played at North Carolina, while Holt was a standout at North CarolinaState. The did a photo shoot together, and Bly said they spoke about five words to each other.

Then, they both ended up with the St. Louis Rams and became best of friends. Bly, an 11-year NFL veteran, credits practicing against Holt and Isaac Bruce for four seasons with the Rams for helping him develop into a starting, producing cornerback in the NFL.

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Brown was beaten for two touchdowns against the Packers. He found himself trailing Greg Jennings on a slant that Jennings took 64 yards for a touchdown. Later, he was playing off Jordy Nelson, who caught a quick hitch, avoided Brown and scored on a 7-yard play.

Why was Brown always playing “off” the Packers? Brown said how the cornerbacks play the receiver is determined by the defensive call. He said he’s not afraid to play press coverage against anyone, but the defense dictated that he play off the line of scrimmage.

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After 4 ½ games as the 49ers’ main man, Alex Smith did a pretty good job of assessing the start of the team’s offense.

“Some good. Some bad. Some in-between.”

Smith said he has no explanation for why his numbers are better when passing out of the shotgun formation.

Smith in shotgun: 58 of 92 (63.0 percent) for 639 with 7 TDs and 3 interceptions – passer rating of 95.3. (Four sacks for minus-29 yards. He’s also had five scrambles for 22 yards.

Linebacker Takeo Spikes, who missed the Packers game with a left hamstring strain, is doing better. But Singletary projected his availability for Sunday’s as a “game-time decision.”

Guard David Baas (ankle), back Michael Robinson (shoulder stinger) and receiver Arnaz Battle (leg strain) are “day to day.” But Singletary said he expects all the players injured in the Packers game to be available this week. That list includes linebacker Patrick Willis (trapezius strain), safeties Mark Roman (rib contusion), Reggie Smith (abdominal strain) and Marcus Hudson (back spasms), and tight end Delanie Walker (forearm contusion).